<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <link rel="stylesheet" href="./css/mui.min.css">
    <style>
        html,
        body {
            width: 100%;
            height: 100%;
            overflow: hidden;
        }

        #demo {
            width: 300px;
            height: 300px;
            background: blue;
        }
    </style>
</head>

<body>
<div class="mui-numbox">
    <!-- "-"按钮，点击可减小当前数值 -->
    <button class="mui-btn mui-numbox-btn-minus" type="button">-</button>
    <input class="mui-numbox-input" type="number" />
    <!-- "+"按钮，点击可增大当前数值 -->
    <button class="mui-btn mui-numbox-btn-plus" type="button">+</button>
</div>
    <script src="./js/mui.js"></script>
</body>

</html>